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PubMed1999

Amine borate catabolism by bacteria isolated from contaminated metal-working fluids

Four bacterial strains (tentatively identified as strains of Aeromonas, Pseudomonas, Flavobacterium and Bacillus) isolated from contaminated metal-working fluids were assayed for the capacity to utilize the borate derivatives of monoethanolamine (MEA), diethanolamine (DEA) and triethanolamine (TEA). Two of these strains, isolates AV1 (Flavobacterium) and CL1 (Bacillus) were capable of growth on each of the borate esters with cell yields of 0.6 gl - 1 for AV1 cultured on DEA- and TEA-borate, 0.3-0.4 gl - 1 for CL1 cultured on DEA- and TEA-borate and approximately 1.4 gl - 1 for AV1 and CL1 cultured on MEA-borate. In the case of strain CL1, growth yields on TEA- or DEA-borate as substrates were doubled by the addition of potassium ions. Lower ethanolamines, glycolaldehyde, acetaldehyde and ammonia were identified as breakdown products. The enzymes produced during growth upon the alkanolamine borates were shown to possess similar properties to those seen for cells cultured upon alkanolamine hydrochlorides.

Journal Article↗

PubMed2002

Diversity of 746 heterotrophic bacteria isolated from microbial mats from ten Antarctic lakes.

Microbial mats, growing in Antarctic lakes constitute unique and very diverse habitats. In these mats microorganisms are confronted with extreme life conditions. We isolated 746 bacterial strains from mats collected from ten lakes in the Dry Valleys (lakes Hoare and Fryxell), the Vestfold Hills (lakes Ace, Druzhby, Grace, Highway, Pendant, Organic and Watts) and the Larsemann Hills (lake Reid), using heterotrophic growth conditions. These strains were investigated by fatty acid analysis, and by numerical analysis, 41 clusters, containing 2 to 77 strains, could be delineated, whereas 31 strains formed single branches. Several fatty acid groups consisted of strains from different lakes from the same region, or from different regions. The 16S rRNA genes from 40 strains, representing 35 different fatty acid groups were sequenced. The strains belonged to the alpha, beta and gamma subclasses of the Proteobacteria, the high and low percent G+C Gram-positives, and to the Cytophaga-Flavobacterium-Bacteroides branch. For strains representing 16 fatty acid clusters, validly named nearest phylogenetic neighbours showed pairwise sequence similarities of less than 97%. This indicates that the clusters they represent, belong to taxa that have not been sequenced yet or as yet unnamed new taxa, related to Alteromonas, Bacillus, Clavibacter, Cyclobacterium, Flavobacterium, Marinobacter, Mesorhizobium, Microbacterium, Pseudomonas, Saligentibacter, Sphingomonas and Sulfitobacter.

Antarctic Regions↗

PubMed2005

Detection of anti-dsDNA by ELISA using different sources of antigens.

AIM: To compare different sources of DNA for use in ELISA-based assays for anti-dsDNA antibody detection in systemic lupus erythematosus (SLE) diagnosis. METHOD: Bacterial genomic DNA from Flavobacterium menignosepticum, Proteus vulgalis, Seratia marcescens, Streptococcus pyogenes and Salmonella typhimurium and genomic DNA from human blood were used as antigens for IgG anti-dsDNA detection by enzyme-linked immunosorbent assay (ELISA). Eighty-six sera were tested, 28 derived from patients with SLE, 28 from patients with other rheumatic diseases and 30 from normal human subjects. RESULTS: Genomic DNA from Flavobacterium menignosepticum and human blood had high sensitivity (75%, 82%) and specificity (91%, 91%) for anti-dsDNA detection in diagnosis of SLE. However, human genomic DNA was the most effective antigen of all antigens studied. The assay had a higher sensitivity but lower specificity than commercial ELISA (61% sensitivity and 95% specificity). There was a high level of correlation between commercial ELISA and ELISA using human genomic DNA as antigen (r=0.776, p<0.001) and they exhibited a high level of diagnostic agreement with each other (kappa=0.890, p<0.001). CONCLUSION: The genomic DNA from human blood is a potentially useful source of antigen for the detection of anti-dsDNA by ELISA. However, further studies are required to compare the performance of ELISA using this source of antigen against commercial radioimmunoassays for anti-dsDNA detection.

Animals↗

PubMed1984

Differentiation between Xanthomonas campestris pv. oryzae, Xanthomonas campestris pv. oryzicola and the bacterial 'brown blotch' pathogen on rice by numerical analysis of phenotypic features and protein gel electrophoregrams.

Thirty-five Xanthomonas campestris pv. oryzae, fourteen X. campestris pv. oryzicola strains and six 'brown blotch' pathogens of rice, all of different geographical origin, were studied by numerical analysis of 133 phenotype features and gel electrophoregrams of soluble proteins, %G + C determinations and DNA:rRNA hybridizations. The following conclusions were drawn. (i) The Xanthomonas campestris pathovars oryzae and oryzicola display clearly distinct protein patterns on polyacrylamide gels and can be differentiated from each other by four phenotype tests. (ii) Both pathovars are indeed members of Xanthomonas which belongs to a separate rRNA branch of the second rRNA superfamily together with the rRNA branches of Pseudomonas fluorescens, Marinomonas, Azotobacter, Azomonas and Frateuria. (iii) 'Brown blotch' strains are considerably different from X. campestris pv. oryzae and oryzicola. They are not members of the genus Xanthomonas, but are more related to the generically misnamed. Flavobacterium capsulatum, Pseudomonas paucimobilis, Flavobacterium devorans and 'Pseudomonas azotocolligans' belonging in the fourth rRNA superfamily. (iv) No correlation was found between the virulence, pathogenic groups or geographical distribution of X. campestris pv. oryzae or oryzicola strains and any phenotypic or protein electrophoretic property or clustering.

Base Composition↗

PubMed1998

rRNA-targeted fluorescent in situ hybridization analysis of bacterial community structure in river water.

An improved in situ hybridization technique, HNPP-FISH, using 2-hydroxy-3-naphthoic acid 2'-phenylanilide phosphate (HNPP) and Fast Red TR was applied to analyse the community structure of planktonic bacteria in river water. Oligonucleotide probes specific for the domain Bacteria (EUB338) and five bacterial groups [Flavobacterium-Cytophaga; Burkholderia-Pseudomonas (rRNA III)-authentic Alcaligenes; Vibrio-Aeromonas; Pseudomonas (rRNA I): the genus Acinetobacter] were used to investigate the bacterial community structure at two sites differing in organic carbon pollution level. At the eutrophic site, 54-68% of all cells visualized by staining with DAPI (4',6-diamidino-2-phenylindole) could be detected with probe EUB338. In samples from the oligotrophic site, 39-45% of the total cells hybridized with EUB338. At the eutrophic site, approximately 50% of the total cells were identified with the five group-specific probes; the bacterial community structure was dominated by the Flavobacterium-Cytophaga group and Burkholderia-Pseudomonas (rRNA III)-authentic Alcaligenes group. At the oligotrophic site, only 26-38% of the total cells were identified with the five group-specific probes. The community structure at the oligotrophic site was similar to that at the eutrophic site, although the percentage of EUB338-detectable cells differed. No appreciable change was found in the community structure during the sampling period at either site. The improved HNPP-FISH technique should be a useful tool for the analysis of microbial community composition.

Bacteria↗

PubMed1977

Microbiological characteristics of Pacific shrimp (Pandalus jordani).

Microorganisms associated with Pacific shrimp (Pandalus jordani) were isolated and identified. Those on the iced raw shrimp, which yielded an average count of 1.6 x 10(6), were predominantly Moraxella, Pseudomonas, Acinetobacter, Arthrobacter, and Flavobacterium-Cytophaga spp. The blanching and peeling reduced the microbial level to 3.3 x 10(4) and also selectively eliminated Moraxella spp. The microbial flora changed after each processing sequence, and the heat sensitivity and growth characteristics of the representative microbial groups suggested that the presence of Arthrobacter and Acinetobacter spp. in peeled shrimp may indicate inadequate cleaning of raw shrimp or a shorter blanching time. The presence of Moraxella and Flavobacterium-Cytophaga spp. would indicate the degree of secondary contamination, and the presence of Pseudomonas spp. would indicate the shelf-age of the processed shrimp.

Animals↗

PubMed1979

Measurement of proteolysis in natural waters.

Microbiological proteolysis in Lake Champlain water was measured in situ and in vitro by the spectrophotometric measurement of the rate of release of soluble color from an insoluble azure dye derivative of hide powder. Water samples sterilized by microfiltration were never proteolytic. In situ proteolysis was found to be very dependent upon water temperature (1 to 23 degrees C). No measurable activity was observed below 4 degrees C. The in vitro proteolysis rate at 20 degrees C was found to be 2.3 times the rate at 15 degrees C and 6 times the rate at 10 degrees C. Water taken from beneath the ice-covered lake throughout the winter and tested in the laboratory at 20 degrees C was found to show an increasing proteolytic potential during the winter months. The highest activity was obtained as the ice broke up in early spring. Microbiological proteolysis in water from Burlington Harbor was often four times that found in center lake water. In most experiments proteolysis was inhibited completely by 2 mug of Cu and inhibited 67% by 0.75 mug/ml. Proteolysis was markedly stimulated by 20 to 40 mug of Casitone or Casamino Acids per ml. The predominant bacteria growing in the proteolysis flasks were species of Pseudomonas and Flavobacterium. Pure cultures of Pseudomonas required traces of Casitone, Casamino Acids, or yeast extract for proteolysis of hide powder azure, whereas those of Flavobacterium did not. The requirement could not be met by a mixture of 21 amino acids and eight vitamins.

Journal Article↗

PubMed1989

Survey of metal tolerance in moderately halophilic eubacteria.

The tolerance patterns, expressed as MICs, for 250 moderately halophilic eubacteria to 10 heavy metals were surveyed by using an agar dilution method. The moderate halophiles tested included 12 culture collection strains and fresh isolates representative of Deleya halophila (37 strains), Acinetobacter sp. (24 strains), Flavobacterium sp. (28 strains), and 149 moderately halophilic gram-positive cocci included in the genera Marinococcus, Sporosarcina, Micrococcus, and Staphylococcus. On the basis of the MICs, the collection strains showed, overall, similar responses to silver, cobalt, mercury, nickel, lead, and zinc. All were sensitive to silver, mercury, and zinc and tolerant of lead. The response to arsenate, cadmium, chromium, and copper was very heterogeneous. The metal susceptibility levels of the 238 freshly isolated strains were, in general, very heterogeneous among the four taxonomic groups as well as within the strains included in each group. The highest toxicities were found with mercury, silver, and zinc, while arsenate showed the lowest activity. All these strains were tolerant of nickel, lead, and chromium and sensitive to silver and mercury. Acinetobacter sp. strains were the most heavy-metal tolerant, with the majority of them showing tolerance of eight different metal ions. In contrast, Flavobacterium sp. strains were the most metal sensitive. The influence of salinity and yeast extract concentrations of the culture medium on the toxicity of the heavy metals tested for some representative strains was also studied. Lowering the salinity, in general, led to enhanced sensitivity to cadmium and, in some cases, to cobalt and copper. However, increasing the salinity resulted in only a slight decrease in the cadmium, copper, and nickel toxicities.(ABSTRACT TRUNCATED AT 250 WORDS)

Eubacterium↗

PubMed1999

Morphological and compositional changes in a planktonic bacterial community in response to enhanced protozoan grazing.

We analyzed changes in bacterioplankton morphology and composition during enhanced protozoan grazing by image analysis and fluorescent in situ hybridization with group-specific rRNA-targeted oligonucleotide probes. Enclosure experiments were conducted in a small, fishless freshwater pond which was dominated by the cladoceran Daphnia magna. The removal of metazooplankton enhanced protozoan grazing pressure and triggered a microbial succession from fast-growing small bacteria to larger grazing-resistant morphotypes. These were mainly different types of filamentous bacteria which correlated in biomass with the population development of heterotrophic nanoflagellates (HNF). Small bacterial rods and cocci, which showed increased proportion after removal of Daphnia and doubling times of 6 to 11 h, belonged nearly exclusively to the beta subdivision of the class Proteobacteria and the Cytophaga-Flavobacterium cluster. The majority of this newly produced bacterial biomass was rapidly consumed by HNF. In contrast, the proportion of bacteria belonging to the gamma and alpha subdivisions of the Proteobacteria increased throughout the experiment. The alpha subdivision consisted mainly of rods that were 3 to 6 microm in length, which probably exceeded the size range of bacteria edible by protozoa. Initially, these organisms accounted for less than 1% of total bacteria, but after 72 h they became the predominant group of the bacterial assemblage. Other types of grazing-resistant, filamentous bacteria were also found within the beta subdivision of Proteobacteria and the Cytophaga-Flavobacterium cluster. We conclude that the predation regimen is a major structuring force for the bacterial community composition in this system. Protozoan grazing resulted in shifts of the morphological as well as the taxonomic composition of the bacterial assemblage. Grazing-resistant filamentous bacteria can develop within different phylogenetic groups of bacteria, and formerly underepresented taxa might become a dominant group when protozoan predation is the major selective pressure.

Animals↗

PubMed2001

Comparison of cellular and biomass specific activities of dominant bacterioplankton groups in stratified waters of the Celtic Sea.

A flow-sorting technique was developed to determine unperturbed metabolic activities of phylogenetically characterized bacterioplankton groups with incorporation rates of [(35)S]methionine tracer. According to fluorescence in situ hybridization with rRNA targeted oligonucleotide probes, a clade of alpha-proteobacteria, related to Roseobacter spp., and a Cytophaga-Flavobacterium cluster dominated the different groups. Cytometric characterization revealed both these groups to have high DNA (HNA) content, while the alpha-proteobacteria exhibited high light scatter (hs) and the Cytophaga-Flavobacterium cluster exhibited low light scatter (ls). A third abundant group with low DNA (LNA) content contained cells from a SAR86 cluster of gamma-proteobacteria. Cellular specific activities of the HNA-hs group were 4- and 1.7-fold higher than the activities in the HNA-ls and LNA groups, respectively. However, the higher cellular protein synthesis by the HNA-hs could simply be explained by their maintenance of a larger cellular protein biomass. Similar biomass specific activities of the different groups strongly support the main assumption that underlies the determination of bacterial production: different bacteria in a complex community incorporate amino acids at a rate proportional to their protein synthesis. The fact that the highest growth-specific rates were determined for the smallest cells of the LNA group can explain the dominance of this group in nutrient-limited waters. The metabolic activities of the three groups accounted for almost the total bacterioplankton activity, indicating their key biogeochemical role in the planktonic ecosystem of the Celtic Sea.

Animals↗

PubMed2001

Bacterial populations colonizing and degrading rice straw in anoxic paddy soil.

Rice straw is a major substrate for the production of methane, a greenhouse gas, in flooded rice fields. The bacterial community degrading rice straw under anoxic conditions was investigated with molecular methods. Rice straw was incubated in paddy soil anaerobically for 71 days. Denaturing gradient gel electrophoresis (DGGE) of the amplified bacterial 16S rRNA genes showed that the composition of the bacterial community changed during the first 15 days but then was stable until the end of incubation. Fifteen DGGE bands with different signal intensities were excised, cloned, and sequenced. In addition, DNA was extracted from straw incubated for 1 and 29 days and the bacterial 16S rRNA genes were amplified and cloned. From these clone libraries 16 clones with different electrophoretic mobilities on a DGGE gel were sequenced. From a total of 31 clones, 20 belonged to different phylogenetic clusters of the clostridia, i.e., clostridial clusters I (14 clones), III (1 clone), IV (1 clone), and XIVa (4 clones). One clone fell also within the clostridia but could not be affiliated to one of the clostridial clusters. Ten clones grouped closely with the genera Bacillus (3 clones), Nitrosospira (1 clone), Fluoribacter (1 clones), and Acidobacterium (2 clones) and with clone sequences previously obtained from rice field soil (3 clones). The relative abundances of various phylogenetic groups in the rice straw-colonizing community were determined by fluorescence in situ hybridization (FISH). Bacteria were detached from the incubated rice straw with an efficiency of about 80 to 90%, as determined by dot blot hybridization of 16S rRNA in extract and residue. The number of active (i.e., a sufficient number of ribosomes) Bacteria detected with a general eubacterial probe (Eub338) after 8 days of incubation was 61% of the total cell counts. This percentage decreased to 17% after 29 days of incubation. Most (55%) of the active cells on day 8 belonged to the genus Clostridium, mainly to clostridial clusters I (24%), III (6%), and XIVa (24%). An additional 5% belonged to the Cytophaga-Flavobacterium cluster of the Cytophaga-Flavobacterium-Bacteroides phylum, 4% belonged to the alpha, beta, and gamma Proteobacteria, and 1.3% belonged to the Bacillus subbranch of the gram-positive bacteria with a low G+C content. The results show that the bacterial community colonizing and decomposing rice straw developed during the first 15 days of incubation and was dominated by members of different clostridial clusters, especially clusters I, III, and XIVa.

Anaerobiosis↗

PubMed2002

Phylogeny of culturable estuarine bacteria catabolizing riverine organic matter in the northern Baltic Sea.

The objective of our study was to isolate and determine the phylogenetic affiliation of culturable estuarine bacteria capable of catabolizing riverine dissolved organic matter (RDOM) under laboratory conditions. Additions of RDOM consistently promoted the growth of estuarine bacteria in carbon-limited dilution cultures, with seasonal variation in growth rates and yields. At least 42 different taxa were culturable on solid agar media and, according to quantitative DNA-DNA hybridizations, constituted 32 to 89% of the total bacterial number in the enriched treatments. Five species in the Cytophaga-Flexibacter-Bacteroides group and one in the gamma-proteobacteria phylogenetic group (Marinomonas sp.) were numerically dominant during the stationary phase of the RDOM-enriched dilution cultures but not in the control cultures. Four of the isolates in Cytophaga-Flexibacter-Bacteroides group were putatively affiliated with the genus FLAVOBACTERIUM: All dominating isolates were determined to be new species based on comparison to the current databases. The same group of species dominated independently of the season investigated, suggesting a low diversity of bacteria catabolizing RDOM in the estuary. It also suggested a broad tolerance of the dominating species to seasonal variation in hydrography, chemistry, and competition with other species. Taken together, our results suggest that a limited group of bacteria, mainly in the Flavobacterium genus, played an important role in introducing new energy and carbon to the marine system in the northern Baltic Sea.

Bacteria↗

PubMed2003

Diversity and structure of bacterial communities in Arctic versus Antarctic pack ice.

A comprehensive assessment of bacterial diversity and community composition in arctic and antarctic pack ice was conducted through cultivation and cultivation-independent molecular techniques. We sequenced 16S rRNA genes from 115 and 87 pure cultures of bacteria isolated from arctic and antarctic pack ice, respectively. Most of the 33 arctic phylotypes were >97% identical to previously described antarctic species or to our own antarctic isolates. At both poles, the alpha- and gamma-proteobacteria and the Cytophaga-Flavobacterium group were the dominant taxonomic bacterial groups identified by cultivation as well as by molecular methods. The analysis of 16S rRNA gene clone libraries from multiple arctic and antarctic pack ice samples revealed a high incidence of closely overlapping 16S rRNA gene clone and isolate sequences. Simultaneous analysis of environmental samples with fluorescence in situ hybridization (FISH) showed that approximately 95% of 4',6'-diamidino-2-phenylindole (DAPI)-stained cells hybridized with the general bacterial probe EUB338. More than 90% of those were further assignable. Approximately 50 and 36% were identified as gamma-proteobacteria in arctic and antarctic samples,respectively. Approximately 25% were identified as alpha-proteobacteria, and 25% were identified as belonging to the Cytophaga-Flavobacterium group. For the quantification of specific members of the sea ice community, new oligonucleotide probes were developed which target the genera Octadecabacter, Glaciecola, Psychrobacter, Marinobacter, Shewanella, and Polaribacter: High FISH detection rates of these groups as well as high viable counts corroborated the overlap of clone and isolate sequences. A terrestrial influence on the arctic pack ice community was suggested by the presence of limnic phylotypes.

Antarctic Regions↗

PubMed2003

Combining culture-dependent and -independent methodologies for estimation of richness of estuarine bacterioplankton consuming riverine dissolved organic matter.

Three different methods for analyzing natural microbial community diversity were combined to maximize an estimate of the richness of bacterioplankton catabolizing riverine dissolved organic matter (RDOM). We also evaluated the ability of culture-dependent quantitative DNA-DNA hybridization, a 16S rRNA gene clone library, and denaturing gradient gel electrophoresis (DGGE) to detect bacterial taxa in the same sample. Forty-two different cultivatable strains were isolated from rich and poor solid media. In addition, 50 unique clones were obtained by cloning of the bacterial 16S rDNA gene amplified by PCR from the community DNA into an Escherichia coli vector. Twenty-three unique bands were sequenced from 12 DGGE profiles, excluding a composite fuzzy band of the Cytophaga-Flavobacterium group. The different methods gave similar distributions of taxa at the genus level and higher. However, the match at the species level among the methods was poor, and only one species was identified by all three methods. Consequently, all three methods identified unique subsets of bacterial species, amounting to a total richness of 97 operational taxonomic units in the experimental system. The confidence in the results was, however, dependent on the current precision of the phylogenetic determination and definition of the species. Bacterial consumers of RDOM in the studied estuary were primarily both cultivatable and uncultivable taxa of the Cytophaga-Flavobacterium group, a concordant result among the methods applied. Culture-independent methods also suggested several not-yet-cultivated beta-proteobacteria to be RDOM consumers.

Bacteria↗

PubMed2004

Bacterial succession in a petroleum land treatment unit.

Bacterial community dynamics were investigated in a land treatment unit (LTU) established at a site contaminated with highly weathered petroleum hydrocarbons in the C(10) to C(32) range. The treatment plot, 3,000 cubic yards of soil, was supplemented with nutrients and monitored weekly for total petroleum hydrocarbons (TPH), soil water content, nutrient levels, and aerobic heterotrophic bacterial counts. Weekly soil samples were analyzed with 16S rRNA gene terminal restriction fragment (TRF) analysis to monitor bacterial community structure and dynamics during bioremediation. TPH degradation was rapid during the first 3 weeks and slowed for the remainder of the 24-week project. A sharp increase in plate counts was reported during the first 3 weeks, indicating an increase in biomass associated with petroleum degradation. Principal components analysis of TRF patterns revealed a series of sample clusters describing bacterial succession during the study. The largest shifts in bacterial community structure began as the TPH degradation rate slowed and the bacterial cell counts decreased. For the purpose of analyzing bacterial dynamics, phylotypes were generated by associating TRFs from three enzyme digests with 16S rRNA gene clones. Two phylotypes associated with Flavobacterium and Pseudomonas were dominant in TRF patterns from samples during rapid TPH degradation. After the TPH degradation rate slowed, four other phylotypes gained dominance in the community while Flavobacterium and Pseudomonas phylotypes decreased in abundance. These data suggest that specific phylotypes of bacteria were associated with the different phases of petroleum degradation in the LTU.

Bacteria↗

PubMed1968

Effect of gamma irradiation on the microflora of freshwater fish. 3. Spoilage patterns and extension of refrigerated storage life of yellow perch fillets irradiated to 0.1 and 0.2 megarad.

Maximal shelf life was determined and microbial flora were compared for irradiated (0.1 and 0.2 Mrad) and nonirradiated yellow perch fillets stored at 1 C. Shelf life was estimated by organoleptic determinations. Microbiological studies included determination of the effects of irradiation on the total aerobic microbial population, lag phase, and rate of growth. Genera of organisms isolated from fillets through the course of microbial spoilage were identified, and the proteolytic activity of the organisms was determined. Plate counts for fish prior to irradiation showed the presence of approximately 10(6) organisms per g of sample. Irradiation to 0.1 and 0.2 Mrad produced 1.4 and 3 logarithm reductions of the initial count, respectively. Irradiation to 0.1 and 0.2 Mrad approximately doubled the product's shelf life. Organisms initially isolated from the nonirradiated fillets, in order of decreasing number, consisted of Flavobacterium, Micrococcus-Sarcina, Achromobacter-Alcaligenes-Mima, Pseudomonas, Microbacterium, Vibrio, Bacillus, Corynebacterium, Lactobacillus, Brevibacterium, and Aeromonas. By the 6th and 9th days of fillet storage, Pseudomonas and the Achromobacter group were the predominant organisms. All members of the genus Flavobacterium, but not all members of the genus Pseudomonas, were proteolytically active on raw fish juice-agar and skim milk-agar media. The Achromobacter group was found to be nonproteolytic on both media. Residual flora of fillets irradiated to 0.1 and 0.2 Mrad consisted of the Achromobacter group, Lactobacillus, Micrococcus-Sarcina, and Bacillus. Their sequence in predominance, however, varied with dose level. Not all proteolytic bacteria in the fillets were eliminated by 0.1 and 0.2 Mrad; proteolytic Micrococcus-Sarcina survived these treatments.

Bacteria↗

PubMed1971

Microbial Flora of Pond-Reared Brown Shrimp (Penaeus aztecus).

Agar plate counts and microbial types are reported for brown shrimp reared in 2-acre natural marshland and in 0.5-acre artificial ponds during June to October 1970. Bacterial counts of pond-reared shrimp ranged from 5 x 10 to 5.5 x 10 per g. At final harvest in October, bacterial counts ranged from 2 x 10 to 5.5 x 10 per g. In marsh ponds, bacterial counts of shrimp and pond water were lowest in August when both water temperature and salinity were high. Coryneform bacteria and to a lesser extent Vibrio were the predominant isolates from fresh pond shrimp. Shrimp stored at 3 to 5 C for 7 days were acceptable as judged by appearance and odor. Between 7 and 14 days of refrigerated storage, bacterial counts increased sharply and about 50% of the samples became unacceptable. Refrigerated storage of pond shrimp caused increases in coryneform bacteria and micrococci and decreases in Vibrio, Flavobacterium, Moraxella, and Bacillus species. Pseudomonas species were not significant in fresh or stored pond shrimp. The microbial flora of pond water usually was dominated by coryneform bacteria, Flavobacterium, Moraxella, and Bacillus species.

Journal Article↗

PubMed1975

Microbiological characteristics of Dungeness crab (Cancer magister).

Aerobic, heterotropic microorganisms of Dungeness crab (Cancer magister) were isolated from raw crab, cooked crab, crab meats obtained during commercial processing, and from retail crab meat samples. Each microbial isolate was then identified to the genus level employing the revised replica plating procedure. Microbial groups most commonly isolated from crab meat were, in the order of predominance, Moraxella, Pseudomonas, Acinetobacter, Arthrobacter, Micrococcus, Flavobacterium-Cytophaga, and Bacillus sp. Proteus, Staphylococcus, yeasts, Vibrio, and Lactobacillus sp. were found less frequetly in some samples. Distribution patterns of microbial flora in crab meat revealed the presence of three classes of microorganisms. Microorganisms that originated from the raw crab and gained predominance by growth during refrigerated storage were Moraxella, Pseudomonas, Acinetobacter, and Flavobacterium-Cytophaga sp. Those that originated from the crab but did not grow in meat were Arthrobacter and Bacillus sp. Micrococcus, Staphylococcus, and Proteus sp. were introduced during processing, but they did not grow in the refrigerated crab meat.

Aerobiosis↗